• 대한의용생체공학회:의공학회지
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• 제31권4호
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• pp.292-301
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• 2010

To restore visual sensation of blind patients, we have proposed a fully implantable retinal prosthesis comprising an three dimensionally (3D) stacked retinal chip for transforming optical signal to electrical signal, a flexible cable with stimulus electrode array for stimulating retina cells, and coupling coils for power transmission. The 3D stacked retinal chip is consisted of several LSI chips such as photodetector, signal processing circuit, and stimulus current generator. They are vertically stacked and electrically connected using 3D integration technology. Our retinal prosthesis has a small size and lightweight with high resolution, therefore it could increase the patients` quality of life (QOL). For realizing the fully implantable retinal prosthesis, we developed a retinal prosthesis module comprising a retinal prosthesis chip and a flexible cable with stimulus electrode array for generating optimal stimulus current. In this study, we used a 2D retinal chip as a prototype retinal prosthesis chip. We fabricated the polymide-based flexible cable of $20{\mu}m$ thickness where 16 channels Pt stimulus electrode array was formed in the cable. Pt electrode has an impedance of $9.9k{\Omega}$ at 400Hz frequency. The retinal prosthesis chip was mounted on the flexible cable by an epoxy and electrically connected by Au wire. The retinal prosthesis chip was cappted by a silicone to pretect from corrosive environments in an eyeball. Then, the fabricated retinal prosthesis module was implanted into an eyeball of a rabbit. We successfully recorded electrically evoked potential (EEP) elicited from the rabbit brain by the current stimulation supplied from the implanted retinal prosthesis module. EEP amplitude was increased linearly with illumination intensity and irradiation time of incident light. The retinal prosthesis chip was well functioned after implanting into the eyeball of the rabbit.

• 대한기계학회논문집B
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• 제37권6호
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• pp.615-620
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• 2013

이전 연구에서 우리는 나노구조와 화학연료의 동축 구조를 제작하여 이를 점화시켰을 때, 축방향으로 매우 빠르게 화학 반응이 전파되며, 이와 동시에 높은 비출력을 가지는 화학-전기 에너지를 생성할 수 있음을 증명하였으며, 이러한 현상을 열동력 파도로 명명하였다. 본 연구에서는 열동력 파도와 관련된 여러가지 물리적인 현상을 심도있게 다루려 한다. 나노구조의 다른 배열 상태에 따라 반응 전파속도, 에너지 생성 정도가 어떻게 달라지는지, 그리고 이와 동시에 발생하는 전기 신호와는 어떤 연관 관계가 있는 지를 연구하였다. 또한 이론적으로 온도 변화에 따라 달라지는 나노튜브와 화학연료의 성질, 대류와 복사에 의한 영향을 고려했을 때 열동력 파도의 전파 양상이 어떻게 달라지는 지를 규명하였다.

• 한국환경과학회지
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• 제19권1호
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• pp.27-37
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• 2010

A system coupled the prognostic WRF mesoscale model and CALMET diagnostic model has been employed for predicting high-resolution wind field over complex coastal area. WRF has three nested grids down to from during two days from 24 August 2007 to 26 August 2007. CALMET simulation is performed using both initial meteorological field from WRF coarsest results and surface boundary condition that is Shuttle Radar Topography Mission (SRTM) 90m topography and Environmental Geographic Information System (EGIS) 30m landuse during same periods above. Four Automatic Weather System (AWS) and a Sonic Detection And Ranging (SODAR) are used to verify modeled wind fields. Horizontal wind fields in CM_100m is not only more complex but better simulated than WRF_1km results at Backwoon and Geumho in which there are shown stagnation, blocking effects and orographically driven winds. Being increased in horizontal grid spacing, CM_100m is well matched with vertically wind profile compared SODAR. This also mentions the importance of high-resolution surface boundary conditions when horizontal grid spacing is increased to produce detailed wind fields over complex terrain features.

• 한국초전도ㆍ저온공학회논문지
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• 제23권2호
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• pp.6-9
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• 2021

단결정의 덩어리 시료로부터 박리된 NbSe₂와 FeSe 박막을 이용한 동종 초전도 vdW 접합을 만들고 저온전도측정을 통해 JJ 효과를 확인하였다. 각 물질의 초전도 틈을 측정하였으며 기존 결과와 잘 일치하는 것을 확인하였다. FeSe 접합의 경우 NbSe₂ 접합과 다르게 JJ가 구현되지 않는 경우가 다수 발생하는데 이는 NbSe₂와 구분되는 FeSe의 특성때문으로 보이며 일관성있는 JJ 구현을 위해서 저온 접합이나 접합 각도 의존성을 통한 향후 연구가 필요하다. 그럼에도 불구하고, 본 연구 결과는 FeSe 2차원 결정을 이용해 JJ가 잘 구현될 수 있음을 실험적으로 보인 첫 사례로서 그 의의를 갖는다.